Spool gun adapter

ABSTRACT

The present disclosure provides a welding system having a welder, a welding gun, and a welding gun adapter, the welding gun being a spool gun with an attached motor. The welding gun adapter receives welding power from the welder, and converts it to output power suitable for driving the motor of the welding gun. The welding gun adapter also uses received welding power from the welder for control power. The present techniques allow for the use of welding guns requiring motor power to be used with any ordinary welder.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of U.S.Provisional Patent Application No. 61/424,151, filed Dec. 17, 2010,entitled “Spool Gun Interface.”

BACKGROUND

The present disclosure relates generally to welding equipment, includingwelders and welding guns. Specifically, the present disclosure relatesto an adapter for use between a welder and a spool gun.

Many small wire welders that are available are equipped with a weldinggun for the purpose of delivering welding wire to a welding arc to beconsumed as a filler metal in a weldment. Typically, the welding wire ispushed through a gun cable by a welding wire drive mechanism located inthe welder. However, when welding with a soft filler metal, such asaluminum, the feeding of the welding wire through the welding gun may beproblematic as soft welding wire is prone to binding in some weldingguns. The welding wire feeding issues encountered may cause temporary ortotal arc outages. In the worst case, the wire may feed back into thewelder, causing a “bird's nest” of welding wire in the welding wiredrive mechanism.

One method for resolving this issue is to employ a welding gun with ashorter welding wire travel path to minimize the welding wirerestrictions. Such a welding gun is known as a “spool gun” because thewelding wire spool and welding wire drive mechanism are located in ahandle end of the spool gun closest to the welding arc. Thisconfiguration allows softer filler metal welding wire to be delivered tothe welding arc in a straight, short (e.g., approximately 10″) path.Since the welding wire spool and welding wire drive mechanism arelocated in the spool gun rather than the welder, power must be providedto the spool gun to drive a motor within the spool gun.

Unfortunately, many existing welders are not readily adaptable to beused with a spool gun. Adapting a spool gun to a welder that is not“spool gun ready” may be an expensive and complicated exercise. Thisproblem is exacerbated when the welder is a relatively low-cost welder.

BRIEF DESCRIPTION

In an exemplary embodiment, a welding system includes a welder, awelding gun, and a welding gun adapter. The welding gun adapter includesa welder interface configured to be coupled to the welder and furtherincludes a welding gun interface configured to be coupled to the weldinggun.

In another embodiment, a welding gun adapter includes a welder interfaceconfigured to be coupled to a welder, a welding gun interface configuredto be coupled to a welding gun, and a circuit board configured toreceive an input voltage from the welder to which the welder interfaceis coupled and output an output voltage to the welding gun to which thewelding gun interface is coupled, wherein the output voltage isdifferent than the input voltage.

In another embodiment, a method includes activating a trigger on thewelding gun, wherein the trigger on the welding gun is configured to bea contact closure switch, closing a welding gun trigger circuit on awelder in response to activating the trigger on the welding gun,outputting a voltage at the welder, receiving the voltage from thewelder at a welding gun adapter, powering a control board in the weldinggun adapter with the received voltage, and driving a motor of a weldinggun with the received voltage, wherein the motor is voltage-controlledthrough pulse width modulation by the control board.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a perspective view of a welding system utilizing a welding gunadapter, in accordance with embodiments of the present disclosure;

FIG. 2 is a diagrammatical representation of the welding system of FIG.1, in accordance with embodiments of the present disclosure;

FIG. 3 is a perspective view of the welding gun adapter, in accordancewith embodiments of the present disclosure;

FIG. 4 is an exploded perspective view of the welding gun adapter havinga housing structure and a circuit board, in accordance with embodimentsof the present disclosure;

FIG. 5 is a block diagram illustrating the functionality of the weldinggun adapter, in accordance with aspects of the present disclosure; and

FIG. 6 is a circuit diagram of the welding gun adapter, in accordancewith aspects of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides a welding system wherein weld outputpower from a welder may be used to provide control power and motor powerto a spool gun via a spool gun adapter. As such, the spool gun adapterpresented herein provides a relatively inexpensive method of operating aspool gun with welders that may not be “spool gun ready.” FIG. 1 is aperspective view of a welding system 10 utilizing such a spool gunadapter. The welding system 10 illustrated in FIG. 1 includes a welder12, a welding gun 14 (e.g., such as a spool gun), a welding gun cable16, and a welding gun adapter 20. In the illustrated embodiment, thewelding gun 14 is a spool gun having a welding wire spool 18, thewelding wire spool 18 being driven by a motor located on the welding gun14. Additionally, the welding system 10 may also include a work clamp 21and a work cable 34. The welding system 10, specifically the welder 12,will typically be coupled to a power source, such as a power grid. Otherpower sources may, of course, be utilized including generators,engine-driven power packs, and so forth. As described in greater detailbelow, the welder 12 may provide control power and motor power to thewelding gun 14 via the welding gun adapter 20.

FIG. 2 is a diagrammatical representation of the welding system 10 ofFIG. 1. As illustrated, the welder 12 receives AC power from a powersource 23 via a power cord 22 and outputs welding power at a welderoutput 24. As illustrated, the welder output 24 includes a positive anda negative terminal. The welding gun 14 is coupled to a wire driveassembly 17 via the welding gun cable 16, the wire drive assembly 17being coupled to the positive terminal of the welder output 24 via. Thewelding gun cable 16 may include a coaxial gas line (passage) inside thecable 16 to allow shielding gas to flow from the wire drive assembly 17to the welding gun 14.

As described in greater detail below, welding power from the welder 12is delivered to the welding gun 14 such that the welding gun 14 mayproduce a welding arc on a workpiece 32. The welding gun 14 willtypically include the welding wire spool 18 of welding wire. The weldingwire is advanced through the welding gun 14 by a welding wire driveassembly, typically through the use of an electric motor under thecontrol of control circuitry within either the welding gun 14 or thewelder 12. The workpiece 32 is coupled to the negative terminal of thewelder output 24 via the work cable 34. The work cable 34, being coupledto the negative terminal of the welder output 24 on one end, may becoupled to the workpiece 32 on the opposing end via the work clamp 21,such that the workpiece 32 is electrically coupled to the negativeterminal of the welder output 24, effectively “grounding” the workpiece32 and completing a circuit from the welder 12 to the welding gun 14 tothe workpiece 32 (via a welding arc) and back to the welder 12.

Additionally, as illustrated, the welder 12 is coupled to the weldinggun adapter 20 via both the positive and negative terminals of thewelder output 24, and supplies power to the welding gun adapter 20. Thewelding gun adapter 20 filters the power received from the welder 12 tobe used for adapter circuit control and motor power for the connectedwelding gun 14. The welding gun 14 also includes a trigger 33, whichwhen triggered, relays a trigger signal to a trigger circuit of thewelder 12 via the welding gun adapter 20. When the trigger 33 of thewelding gun 14 is triggered, the welder 12 supplies weld power to thewelding gun 14 for establishing an arc, and to the welding gun adapter20 for control power and power to drive the motor of the welding gun 14.Thus, when the trigger 33 of the welding gun 14 is triggered, thewelding wire spool 18 feeds welding wire through the welding gun 14 tothe welding arc created by welding power from the welder 12. As aresult, the weld wire is molten, and a weld is made on the workpiece 32.In addition, in certain embodiments, the welding gun adapter 20 includescontrol circuitry, which regulates the feeding of welding wire from thewelding wire spool 18 of the welding gun 14.

In certain embodiments, the welder 12 is also coupled to a shielding gassource 35 via a gas hose 36. To shield the weld area from being oxidizedor contaminated during welding, to enhance arc performance, and toimprove the resulting weld, the welder 12 feeds the shielding gas to thewelding gun 14 via the welding gun cable 16, as previously mentioned. Avariety of shielding materials for protecting the weld location may beemployed, including inert shielding gas, including active gases, andparticulate solids.

FIG. 3 is a perspective view of an exemplary welding gun adapter 20. Asillustrated, the welding gun adapter 20 includes an adapter housing 38having a top cover 40 and a bottom cover 42. The welding gun adapter 20also includes a welder connector 44 disposed on one side of the weldinggun adapter 20. The welder connector 44 further includes fourconnections configured to connect to the welder output 24 terminals andthe welder trigger circuit, as described above. Additionally, a weldinggun connector 46 is disposed on another side of the welding gun adapter20. The illustrated welding gun connector 46 includes a 4-pin receptorfor receiving and coupling to the welding gun 14 via the welding guncable 16. In certain embodiments, the welder connector 44 and thewelding gun connector 46 may include different connector types otherthan those shown in FIG. 3. Likewise, certain embodiments may includewelder connectors 44 and welding gun 46 connectors having differentphysical attachment mechanisms such as clips, locks, and so forth.Moreover, in certain embodiments, the physical location of the welderconnector 44 and the welding gun connector 46 may be different thanshown in FIG. 3.

Additionally, in certain embodiments, the welding gun adapter 20includes a knob 48 disposed on a surface of the welding gun adaptor 20.The knob 48 provides a user interfacing mechanism that may be used tocontrol the motor speed of the motor of the welding gun 14, how fastwelding wire is delivered from the welding wire spool 18, and so forth.In certain embodiments, the knob 48 may be replaced with other userinterfacing mechanisms for controlling motor speed, such as switches,buttons, sliders, and so forth. The welding gun adapter 20 may alsoinclude a physical attachment mechanism for securing the welding gunadapter 20 to the welder 12 as configured in FIG. 1. The attachmentmechanism may include clips, holders, adhesives, and so forth. Incertain embodiments, the welding gun adapter 20 may be configured to beattached to the welding gun 14. In other embodiments, the welding gunadapter 20 may be part of a cable connecting the welding gun 14 to thewelder 12. The welding gun adapter 20 illustrated in FIG. 3 is one ofmany possible configurations of the welding gun adapter 20, includingthose of different size, shape, and arrangement of elements.Furthermore, certain embodiments may include other elements, such asadditional inputs, outputs, and user interfacing elements that are notshown in the embodiment illustrated in FIG. 5.

FIG. 4 is an exploded perspective view of the welding gun adapter 20 ofFIG. 3. As illustrated, the welding gun adapter 20 includes a circuitboard 50 disposed between the top cover 40 and the bottom cover 42 ofthe adapter housing 38. The circuit board 50 includes electroniccomponents configured to establish an adapter circuit for carrying outthe disclosed techniques, such as receiving power from the welder 12 andproviding control power and motor power to the welding gun 14, thedetails of which are described in greater detail below. As illustratedin FIG. 4, the welder connector 44 is coupled to the circuit board 50such that the power received from the welder 12 enters the adaptercircuit, and also such that the trigger circuit of the welder 12 iscoupled to the adapter circuit via the welder connector 44. Likewise,the welding gun connector 46 is also coupled to the circuit board 50.The welding gun adapter 20 couples to the welding gun 14 via the weldinggun connector 46, providing power to the welding gun 14 and receiving atrigger signal from the trigger 33 of the welding gun 14. As such, thetop cover 40 includes a through hole 45 which allows the welding gunconnector 46 to be exposed when the adapter housing 38 is closed.

The circuit board 50 also includes a potentiometer 56 coupled to theadapter circuit. The potentiometer 56 is physically coupled to the knob48 disposed on the surface of the welding gun adapter 20 such that thepotentiometer 56 turns in a proportional manner when the knob 48 isturned. This allows a user to control the potentiometer 56, and hencethe motor voltage and motor speed using the welding gun adapter 20. Asillustrated, the circuit board 50 is disposed inside the adapter housing38 such that the top cover 40 and the bottom cover 42 fully enclose thecircuit board 50 when closed. Additionally, the circuit board 50 issupported and stabilized inside the adapter housing 38 by a plurality ofscrews 52 and standoffs 54. In the illustrated embodiment, the standoffs54 are attached to the bottom cover 42 such that the circuit board 50may be configured to sit on top of the standoffs 54, leaving spacebetween the circuit board 50 and the inside surface of the bottom cover42, thereby enabling heat dissipation within the welding gun adapter 20.The standoffs 54 are designed to receive and hold a respective screw 52.Accordingly, the circuit board 50 also includes screw holes establishedon the circuit board 50 at corresponding locations such that the screwholes are generally aligned with the standoffs 54. Screws 52 areinserted into the screw holes of the circuit board 50 and screwed intothe standoffs 54 such that the circuit board 50 is secured between thescrew heads and the standoffs 54, and secured to the bottom cover 42. Inthe illustrated embodiment, the standoffs 54 and screw holes aregenerally placed near the edges of the bottom cover 42 and atcorresponding locations on the circuit board 50, respectively. Incertain embodiments, the standoffs 54 and screw holes may be placed invarious locations and be varied in number. In some embodiments, thestandoffs 54 may be attached to the top cover 40 rather than the bottomcover 42, with the circuit board 50 being secured to the top cover 40rather than the bottom cover 42. Additionally, in certain embodiments,the circuit board 50 may be disposed and secured within the adapterhousing 38 in a manner different than that described above. For example,the circuit board 50 may be held by grooves along inside edges of theadapter housing 38, or held by clips, and so forth.

The top cover 40 and the bottom cover 42 may be joined together toencase the circuit board 50, as shown in FIG. 3. In the illustratedembodiment, the top cover 40 and the bottom cover 42 are secured in aclosed position by screws 52 that screw into and past the bottom cover42 into screw receptacles at corresponding locations in the top cover40. Thus, the screws 52 thread the bottom cover 42 and top cover 40together, holding the top and bottom covers 40, 42 in a joined andclosed position, housing the circuit board 50 inside. Alternatively, theadapter housing 38 may be joined together in a manner different thatdescribed above. For example, the adapter housing 38 may be closed bysliding one cover onto the other, employing a latch or clip closingmechanism, and so forth. In certain embodiments, the adapter housing 38may instead be a one-piece housing, removing the need for top and bottomcovers 40, 42.

Regardless of the specific features of the adapter housing 38, it isnoted that the welding gun adapter 20 is relatively simple in design,including a relatively small number of main components (e.g., theadapter housing 38, the circuit board 50 that includes the adaptercircuit, the potentiometer 56 connected to the knob 48, the welderconnector 44, and the welding gun connector 46). As such, the weldinggun adapter 20 may be manufactured relatively inexpensively, whileproviding the valuable benefit of adapting welders that are not “spoolgun ready” with spool guns, such as the welding gun 14 described herein.

FIG. 5 is a block diagram of certain functionality of the adaptercircuit 72 of the welding gun adapter 20 derived from the more detailedcircuit diagram of the adapter circuit 72 illustrated in FIG. 6. Assuch, FIGS. 5 and 6 will be generally referred to concurrently todisclose both the theory and specific implementation of each portion ofthe adapter circuit 72 of the welding gun adapter 20 described herein.It will be appreciated that the functionality and associated circuitryof the adapter circuit 72 illustrated in FIGS. 5 and 6 is embodied onthe circuit board 50 illustrated in FIG. 4. As illustrated in FIG. 5,the adapter circuit 72 of the welding gun adapter 20 generally includesa rectifier 58, a filter 60, a regulator 62, a motor control relay 64, apulse width modulator 66, an optical isolator 74, and the potentiometer56. As illustrated, the adapter circuit 72 of the welding gun adapter 20also interacts with a motor 70 of the welding gun 14.

Referring now to FIG. 6, as described above, in certain embodiments, thewelding gun adapter 20 may include four connections to the welder 12(e.g., via the welder connector 44 illustrated in FIGS. 3 and 4). Two ofthe connections are power input connections 68 which connect to thewelder output 24 of the welder 12. The other two connections are triggercircuit connections 76 connected to the trigger circuit of the welder12. Specifically, welder output power enters the welding adapter 20through two of the four input receptacles (e.g., the power inputconnections 68) of the welder connector 44, one being a positiveterminal and one being a negative terminal. The voltage received fromthe welder 12 is typically rectified by the rectifier 58, such that theconnections are not polarity sensitive. The rectifier 58, the specificdesign of which is shown in FIG. 6, employs a diode bridge forrectifying the input voltage. The rectified voltage is generallyfiltered to approximately a +30 VDC supply by the filter 60. In theillustrated embodiment, this function may be accomplished by a pluralityof capacitors, as shown. The filtered +30 VDC supply may provide motorpower for the motor 70 of the welding gun 14. The filtered voltage istypically regulated to produce a +15 VDC supply, which generallyprovides control power for the welding gun adapter 20. In theillustrated embodiment, the regulator 62 employs a linear regulator asshown in FIG. 6.

As described above, the welding gun adapter 20 includes four connectionsto the welder 12, two being the power input connections 68 as discussedabove. The remaining two connections are trigger circuit connectors 76,which connect the welding gun adapter 20 to the welding gun triggercircuit of the welder 12. The adapter circuit 72 is also connected tothe trigger circuit of the welding gun 14 via the welding gun connector46 (as illustrated in FIGS. 3 and 4). The welding gun connector 46 alsoincludes four connections, two of which are for delivering motor powerto the welding gun 14 (e.g., motor power connectors 71), and two ofwhich are for communicating a trigger signal (e.g., gun triggerconnectors 73) from the trigger 33 of the welding gun 14 to the adaptercircuit 72.

The welding gun trigger circuit and the welder trigger circuit arecoupled through circuitry in the adapter circuit 72 to form a systemtrigger circuit. As such, when the trigger 33 of the welding gun 14 isactivated, a trigger signal is transmitted from the welding gun 14 tothe welder 12. This allows the welder 12 to respond to the triggering ofthe welding gun 14 by providing power, etc. In contrast withconventional welding gun trigger circuits which generally reference acontrol voltage common to detect triggering, the gun trigger circuit ofthe welding gun adapter 20 works from a simple contact closure. Morespecifically, to overcome the lack of control circuit voltage common,the optical isolator 74 is employed to sense current in the systemtrigger circuit, as opposed to trying to sense voltage. When the trigger33 is depressed or activated in the welding gun 14, the trigger signalis transmitted to the adapter circuit 72 via the gun trigger connectors73, and the trigger circuit is closed. Current then flows from oneterminal of the welder trigger receptacle (e.g., the trigger circuitconnections 76) into the welding gun adapter 20, through a rectifyingdiode bridge 77, and through the optical isolator 74. As such, theconnection is not polarity sensitive due to the rectifying diode bridge77.

In certain embodiments, the optical isolator 74 includes alight-emitting diode and a photo-sensitive transistor. When currentflows through the trigger circuit as a result of the gun triggerclosure, the light-emitting diode lights, which bias the transistor onand turn the optical isolator 74 on. A gun trigger monitor toggles to anon state condition when the optical isolator 74 is turned on, as thewelding gun 14 has been triggered. Additionally, when the opticalisolator 74 turns on, current flows through the device, energizing themotor control relay 64. When the motor control relay 64 is energized,the normally-closed contacts that are connected across the spool gunmotor winding are opened, and the normally-open contacts are closed,connecting the adapter circuit 72 to the control common, which allowsmotor current to flow.

When the motor control relay 64 is de-energized, the normally-closedcontacts that are connected across the spool gun motor winding areclosed, and the normally-open contacts are opened, disconnecting theadapter circuit 72 from control common, halting the motor current. Thenormally-closed contact closure across the motor winding acts as a“dynamic brake” for the motor 70, causing it to immediately stop with nocoasting. This prevents the welding gun 14 from sending excess weldingwire to the weld puddle after power from the welder output 24 of thewelder 12 has been removed.

The pulse width modulator 66 controls the voltage, and thus speed, ofthe welding gun motor 70, which is also activated when the triggercircuit is enabled. The pulse width modulator 66 receives a referencevoltage from the potentiometer 56, which outputs a voltage representingthe desired motor speed as input by the user. The reference voltage fromthe potentiometer 56 is compared against a feedback voltage from thewelding gun motor 70 by an operational amplifier 78. An error signal isgenerated from the difference between the reference voltage and thefeedback voltage, representing the difference between the desired speedof the welding gun motor 70 and the actual speed of the welding gunmotor 70. The error signal is supplied to a compensation pin of thepulse width modulator 66. As the speed of the welding gun motor 70 isdetermined by the feedback voltage, the pulse width modulator 66regulates the voltage supplied to the welding gun motor 70 such that thespeed of the welding gun motor 70 matches the desired speed. The pulsewidth modulator 66 regulates the welding gun motor 70 such that all ofthe motor control voltage levels are below the weld output voltagelevel.

In the present embodiment, the disclosed power characteristics of thesystem include a filtered +30 VDC supply for powering the welding gunmotor 70 and a regulated +15 VDC supply for powering the control circuitof the welding gun adapter 20. Alternate embodiments may be configuredto provide different voltages for these functions.

Additionally, the functional elements of the welding gun adapter 20 aswell as the circuit elements and layout of the welding gun adapter 20 asillustrated in FIGS. 5 and 6 are representative in nature, and providean exemplary schematic of the adapter electronics. It will be understoodthat the novel techniques of the present disclosure may be realized withdifferent electronic elements and a circuit layout different than theone illustrated in FIGS. 5 and 6. For example, referring to FIG. 5, thewelding gun adapter 20 may be realized without a rectifier 58 whilepreserving the novelty and technological advancement of the presentdisclosure. Certain embodiments may also employ different techniques forconverting welding power received and transformed into the control powerand motor power in place of the techniques described above.

As described above, the welding system 10 provides the welding gunadapter 20 for powering the motor 70 of the welding gun 14 using weldpower from the welder 12. The welding gun adapter 20 also obtains itscontrol power from the welder 12, eliminating the need for a separatepower supply. The welding gun adapter 20 is relatively small in size,providing maneuverability and ease of use, though it may be configuredto have a variety of shapes and sizes. The connections to the welder 12and the welding gun 14 are intuitive and self-rectifying, reducing tothe possibility of malfunctioning of the welding system 10. The weldingsystem 10 allows the welding gun 14 to use shielding gas directly fromthe welder 12, rather than requiring a separate source. In addition, thewelding gun adapter 20 is configured to receive an input ofapproximately 30 VDC from the welder 12, and to output a lower DCvoltage to the welding gun 14, the welding gun 14 typically being a 12Vwelding gun. In certain embodiments, approximately 17.5 VDC may beprovided to the welding gun 14. However, certain embodiments may beconfigured to be used with a welding gun 14 having a different voltage,such as a 24V welding gun. Such embodiments may include a boost circuitin the welding gun adapter 20 to boost the received welder power suchthat the voltage provided to the welding gun 14 for motor power isincreased. Thus, a motor 70 with higher voltage needs may be supportedby the welding gun adapter 20.

While only certain features of the invention have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the true spirit of the invention.

The invention claimed is:
 1. A welding spool gun adapter, consistingessentially of: an adapter housing comprising a top cover and a bottomcover; a welder interface comprising a side of the adapter housingabutting the top and bottom covers, wherein the welder interface isconfigured to be coupled to a welder; a welding spool gun interfaceextending through the top cover of the adapter housing; wherein thewelding spool gun interface is configured to be coupled to a weldingspool gun having a welding wire spool driven by a welding wire spoolmotor disposed in the welding spool gun; a circuit board enclosed withinthe adapter housing wherein the circuit board is configured to receivean input voltage via the welder interface from the welder to which thewelder interface is coupled and to output an output voltage via thewelding spool gun interface to the welding spool gun to which thewelding spool gun interface is coupled, wherein the output voltage isdifferent than the input voltage, and wherein the circuit boardcomprises a control circuit configured to provide controls for thewelding spool gun, wherein the control circuit is configured to bepowered by the input voltage received from the welder, wherein thecontrols for the welding spool gun comprise controls for receiving atrigger command from the welding spool gun to which the welding spoolgun interface is coupled, and for providing response commands formanipulating the output voltage to drive the welding wire spool motor ofthe welding spool gun; and a motor speed adjustment knob disposed on thetop cover of the adapter housing, wherein the motor speed adjustmentknob enables a user to manually adjust a relationship of the inputvoltage that is received via the welder interface to the output voltagethat is output via the welding spool gun interface, wherein the outputvoltage usable to adjust a speed of the welding wire spool motor of thewelding spool gun.
 2. The welding spool gun adapter of claim 1, whereinthe welding wire spool motor of the welding spool gun is configured tobe voltage-controlled through pulse-width modulation.
 3. The weldingspool gun adapter of claim 1, wherein the welder interface comprises aconnection to a welding trigger circuit of the welder.
 4. The weldingspool gun adapter of claim 3, wherein the welding trigger circuit of thewelder is controlled by a contact closure.
 5. The welding spool gunadapter of claim 1, wherein the circuit board is configured to receivethe input voltage of approximately 30 volts DC, and the circuit board isconfigured to output the output voltage of approximately 12 volts DC. 6.The welding spool gun adapter of claim 1, wherein the circuit board issupported and stabilized inside the adapter housing by a plurality ofstandoffs extending from the top cover or the bottom cover and havingscrew holes through which screws may be inserted to hold the top andbottom covers together.
 7. The welding spool gun adapter of claim 1,wherein the top and bottom covers are made of a plastic material.
 8. Thewelding spool gun adapter of claim 1, wherein the motor speed adjustmentknob is coupled to a potentiometer of the circuit board configured toenable adjustment of the speed of the welding wire spool motor of thewelding spool gun.
 9. The welding spool gun adapter of claim 1, whereinthe motor speed adjustment knob is the only input device of the weldingspool gun adapter.
 10. The welding spool gun adapter of claim 1, whereinthe welding spool gun adapter receives a constant weld voltage from thewelder via the welder interface, and outputs a lower DC voltage to thewelding spool gun via the welding spool gun interface.
 11. The weldingspool gun adapter of claim 10, wherein the welding wire spool motor ofthe welding spool gun is powered by the lower DC voltage received fromthe welding spool gun adapter.
 12. The welding spool gun adapter ofclaim 1, wherein the welder interface comprises a positive connection toa positive terminal of the welder and negative connection to a negativeterminal of the welder.
 13. The welding spool gun adapter of claim 1,wherein the circuit board is powered by the input voltage.
 14. Thewelding spool gun adapter of claim 1, wherein the adapter housingcomprises one or more attachment mechanisms to hold the top and bottomcovers together.